Goaltender Linus Ullmark made 48 saves and Dylan Cozens scored his first goal as a Senator, giving Ottawa a 2-1 win over the Wings.
David Perron, who played with the Red Wings from 2022-24, broke the ice in Canada’s capital by burying a wrister from the left face-off circle for a power-play goal to give the Senators a 1-0 lead at 7:39 of the second period.
The Detroit Red Wings have lost five games in a row, and captain Dylan Larkin acknowledged their confidence is shaken.
The Red Wings (30-28-6, 66 points) have lost six in a row, sliding further out of the playoff picture. Detroit is four points behind Columbus for the second wild card spot and five points back of Ottawa (33-25-5, 71 points), which moved into the top wild card position.